Joe,
My 265/35 leaves a "footprint" of 9+" of very black, smokey stuff (and that's running 49 to 51# air) 8) ....my 230 and the 280 never left more then 4" wide mark under power, even trying to run 'soft'. Car tires tend not to 'grow' quite as bad under power (especially with low aspect ratios)and therefore their contact patch stays the same. I'm not a tire engineer (or any other kind), but I can tell you that when Wag & I leave marks, it is very easy to determine my "signature" from his :lol:
My Sumitomo is WAY better traction than either the Avon or Metzler. I think this is where talking to guys like Marv makes a difference before purchasing tires. They have tried literally hundreds on actual bikes and have found the limits. On their bikes running the 15" wheels, they pretty much always run Mickey Thompson to get good traction and driveability.
I rode a customers bike @ Marvs running a 15" M/T tire and it hooked up great and very easy to ride.
But like I said at the outset of your thoughts about experimenting, the car tire is not for everyone. It did take me awhile to get used to it and trust it in the turns, and after 4000 miles it still has its' down side, or at least needing to be aware of its handling characteristic in certain situations. I ride a lot of country 2 lane twisties and don't mind it.
If I was going to run my bike purely as a cruiser, I would definitely go back to the Avon, but I tend to spend a lot of time screwing around and like the bike to 'leave' when I want it to. I also didn't like the sideways launch from the round tires, which disappeared with the Sumi.
Like you & Tommy said, it's a good thing to experiment and find out if it's right for your style. You were smart going to the 15" tire to eliminate the need for new wheels, it was a relatively inexpensive experiment and answered your questions.
Tim